Interaction of Cu,Zn superoxide dismutase with hydrogen sulfide.
Interaction of Cu,Zn superoxide dismutase with hydrogen sulfide.
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DOI：
10.1006/abbi.1995.1228
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发表时间：
1995-04
影响因子：
3.9
通讯作者：
Dennis G. Searcy;J. Whitehead;M. Maroney
中科院分区：
文献类型：
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作者：
Dennis G. Searcy;J. Whitehead;M. Maroney
添加HS-可使牛红细胞铜锌超氧化物歧化酶(EC 1.15.1.1)清除O(2-)的能力提高一倍左右。积极的影响是通过多种选择的超氧化物歧化酶活性分析来衡量的，不可能是任何单一技术所限制的人工制品。HS-的Km值在不同的检测技术中有所不同，但我们估计Km约为80微米Hs-。与HS-相反，用超氧化物歧化酶检测的其他小分子要么几乎没有作用，要么具有抑制作用。HS-和O2-的消耗几乎为1：1摩尔比。产物为双氧水和硫磺，如单质硫或多硫化物。HS-与酶结合迅速，K>；10(7)M-1与S-1结合。所得络合物在345 nm处有一个铜-S电荷转移吸收带和一个改变的铜(II)电子顺磁共振光谱。综上所述，这些观察结果表明，HS-结合在SOD的催化铜中心，可能是该酶的真正底物。
Addition of HS- enhanced the O(2-)-scavenging activity of bovine erythrocyte Cu,Zn superoxide dismutase (EC 1.15.1.1) by about twofold. The positive effect was measured using a diverse selection of SOD activity assays, and cannot be an artifact restricted to any single technique. Km values for HS- varied in different assay techniques, but we estimate Km approximately 80 microM HS-. In contrast to HS-, other small molecules tested with SOD either had little effect or were inhibitory. Consumption of HS- and O2- occurred in nearly 1:1 mole ratio. The products were H2O2 and sulfane sulfur, such as either elemental sulfur or polysulfide. Binding of HS- to the enzyme was rapid, with k > 10(7) M-1 s-1. The resulting complex exhibited a Cu-to-S charge-transfer absorbance band at 345 nm and an altered Cu(II) EPR spectrum. Taken together, these observations suggest that HS- binds at the catalytic Cu center of SOD and can be a genuine substrate of the enzyme.